Fukushima Nuclear Reactors Need Reinforcing, Seismic Study Says

Feb. 15 (Bloomberg) -- Areas around the Fukushima Dai-Ichi
nuclear plant appear more prone to large temblors since last
year’s magnitude 9 quake, according to a peer-reviewed
geological study that recommends reinforcing the reactors.

The March 11 earthquake’s strongest on-shore aftershock, a
magnitude 7 quake that struck on April 11, occurred on the Iwaki
fault. This suggests the Iwaki fault has been reactivated by the
record quake a month earlier, according to the study published
yesterday in the journal Solid Earth.

That should prompt closer attention to the seismic safety
of Tokyo Electric Power Co.’s nuclear plant, according to the
researchers at Japan’s Tohoku University in Sendai and Tsinghua
University in Beijing who wrote the study in the journal
published by the European Geosciences Union.

“The similar structures under the Iwaki source area and
the Fukushima nuclear power plant suggest that the security of
the nuclear power plant site should be strengthened to withstand
potential large earthquakes in the future,” they wrote.

Sensors detected 24,108 tremors in the area between the
April 11 aftershock and Oct. 27 last year, with 23 of them
earthquakes of magnitude 5 or higher, according to the study.
That compares to 1,215 recorded between June 3, 2002 and the
March 11 quake, the report shows.